The title for this multi-site program grant application (PO1) is "Early Caries Detection and Intervention." One of the goals of this P01 is to determine the ability of various diagnostic techniques to measure early changes in enamel demineralization. Currently available techniques include quantitative light fluorescence (QLF), infrared laser fluorescence (IR), and electrical conductivity (EC). There is a tremendous need to validate the application of all new developing clinical detection methods, both for primary and secondary caries. It has been stated that "The Diagnosis of early care lesions can be regarded as the cornerstone of cost- effective health care delivery and quality of dental care." (ORCA Symposium on Caries Diagnosis). Three projects will be used to validate the use of these newer diagnostic techniques and then apply those techniques in clinical trials of both primary (Indiana, Proj. 3) and secondary caries (Texas/Indiana, Proj. 2). The interventions will first be tested in Project 1 for effectiveness and if acceptable used as an intervention for primary and/or secondary clinical caries trials. Teeth that are exfoliated during the trials will be analyzed at Iowa for the presence and/or extent of lesion formation using polarized light microscopy as the "gold standard" The interrelationships between the projects and complimentary nature of the research objectives will produce a synergism that offers far more than merely individual projects at individual sites. These series of studies are expected to: 1) Validate new imaging technologies for the detection of both primary and secondary dental caries at a much earlier stage of development than is currently possible; 2) Determine the most effective intervention methods using the appropriate in vitro and in situ models; 3) Use these early caries detection methods to monitor clinically effective interventions for primary and secondary caries. An Administrative Core and a Biostatistics Core will support the projects. The project director will receive advice and review from both an internal Steering Committee and External Advisory Committee. The collaborative efforts of the three research-intensive Universities, the long- standing expertise and diverse populations offer a unique combination of resources for this P01.